Heat cooks up unhealthy air

July 20, 2011

The city and collar counties are under an air pollution alert Wednesday because of excessive smog, and officials have just extended the alert through Thursday. They say Chicago’s northern suburbs and the lakefront are expected to be hardest hit.

Smog, or ground-level ozone, forms when two chemicals mix in the heat and sun. The chemicals can come from car exhaust, power plants, paints or solvents, and the hotter it is, the faster they mix.

Ozone is good when it’s high up in the atmosphere, but at ground-level it can irritate the lungs and airways. Dr. Kyle Hogarth, a pulmonary specialist at the University of Chicago Medical Center, says he often sees an uptick in calls and clinic visits on days like this.

“I think it’s great that there’s these, you know, ozone action days,” says Hogarth. “But to be honest with you, every one of the people with lung disease, they know it before anybody announces it on TV or the radio. I mean they step outside, and they can feel it already.”

Officials are warning that people with lung conditions, as well as the very young and very old, should limit their outdoor exposure. This is the second air pollution action day alert this season.